fix(ci): revert claude-code-review workflow to use checkout@v5

The claude-code-review workflow must match the version on main branch
for GitHub's workflow validation to pass. Keeping it at v5 to match main.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <[email protected]>

Author: fclairamb

.github/workflows/claude-code-review.yml

@@ -27,7 +27,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v5
         with:
           fetch-depth: 1